Issue Summary

Card cover images are rendering as solid black when the file has # character in the filename

Steps to Reproduce

1. Have an image that has # in the name. Example: mypicture #001.png
2. Upload this image as an attachment (you will notice thumbnails does not displays correctly)
3. Add it as a card cover

Expected Results

The card cover displays the image selected

Actual Results

A black cover shows instead, and the attachment thumbnail also didn't load properly

Workaround

Update the file name of the image, removing the # character